There's now a new way to do redlining in Map Server 2013 in your browser, and it includes saving your work, working with multiple layers, and control over the appearance.
Just click the Redline button, and you're on the way!
Just two notes: be sure to get your styles just right before adding the layer to the map - they aren't editable from the browser. And, in order to save the redline layer, you have to "Remove from Map" in the lower pane. That will move it to the upper pane, where you can then Download, which saves an SDF locally.
Have fun with it!